Method and apparatus for treatment of a battery containing alkali metal

ABSTRACT

A safe and controllable method of treating a secondary battery having at least one component containing alkali metal, comprises the steps of opening the battery casing, and introducing a gas containing at least one of water vapor and alcohol vapor into a closed chamber containing the battery thereby to form alkali metal hydroxide. To control hydrogen concentration, the rate of introduction of water and/or alcohol vapor may be varied. Apparatus for carrying out this method is also described.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a method of treating a secondary batteryhaving at least one component containing alkali metal, e.g. lithium, andto apparatus for treatment of such a battery, in order to enable safeextraction and recovery of the alkali metal and optionally othercomponents. In batteries, alkali metal may be present as the metal or inalloy form or as an intercalation compound, and the invention isapplicable to all these forms.

2. Description of the Prior Art

A high energy density battery such as a lithium battery includes anactive material of its negative electrode in the form of highly reactivealkali metal and an electrolytic solution containing LiPF₆ or LiAsF₆which are reactive with water to produce HF. The battery typicallyfurther includes a positive electrode containing metal componentscapable of being regenerated. However, there has been not described anymethod of industrially processing spent batteries such as lithiumbatteries or any apparatus for processing such batteries.

The demand for high energy density batteries shows a yearly increase,and problems arise in terms of effective utilisation of chemicalmaterials used in secondary batteries and of environmental pollutioncaused by batteries. For example, lithium and transition metal elements(Mn, Co) used in a lithium battery are valuable materials suitable to beregenerated. Moreover, a lithium secondary battery capable of beingcharged and discharged has been extensively used as a power supply forback-up of a computer or a power supply of small size domestic electricequipment, and is expected to be used for power storage or as a futurepower supply for an electric automobile. Accordingly, there must bedeveloped a method of processing batteries and a method regeneratingbattery materials for suppressing environmental pollution due tochemical materials contained in the spent batteries and for effectivelyrecovering such components used in batteries.

European patent application 94105151.8 (now published as EP-A-618633)and pending U.S. patent application Ser. No. 08/220,220 describe aprocess of treating a lithium battery by contacting the lithium in thebattery with a liquid alcohol, to form an insoluble reaction product,followed by supply of liquid water and alcohol to form LiOH. Thesolution of LiOH in water and alcohol can then be withdrawn from thebattery. The present invention takes a different approach to theproblem.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a method of treating abattery containing an alkali metal component which is excellent insafety and efficiency, and enables recovery of chemical materialscapable of being regenerated, and to provide an apparatus for processinga battery accordingly.

The present inventors have analysed the problem of treating batteriescontaining alkali metal and reached the following conclusions.

Since a high energy density battery using an alkali metal, such as alithium battery, contains active materials, i.e. reactive alkali metaland electrolytic solution which is unstable in contact with water vapor,attention should be paid to controlling the atmospheric gas whendestroying a battery vessel. For example, the negative electrode of alithium battery utilises lithium metal, a lithium alloy, an intercalatedlithium compound or a carbon compound electrochemically containinglithium, any of which reacts strongly with water to generate hydrogengas. Moreover, a nonaqueous electrolytic solution containing a fluorinecompound such as LiPF₆ reacts with a water content in air, possibly togenerate a harmful gas such as pentafluorophosphide or hydrogenfluoride. Accordingly, to destroy the vessel of a high energy densitybattery using an alkali metal and to expose battery components, thehumidity of the external gas is desirably controlled.

To inactivate a high energy density battery with safety, the followingfunctions may be performed: the battery casing is opened in a dryatmosphere and then reactive battery components and electrolyticsolution are decomposed in a controlled atmosphere based on an inertgas, nitrogen gas or air. Moreover, to suppress the abrupt decompositionof such active components of the battery and prevent explosion of aninflammable gas such as hydrogen, and to shorten the decomposition timeas much as possible, it is desirable to use a method of controlling thedecomposition rate. In the case where the concentration of valuablematerial contained in the waste liquid obtained after processing of thebattery is low, there may be required an enriching process; accordingly,to improve the regenerating efficiency of valuable materials and toshorten the battery processing time, it is desirable tofractional-recover the battery processing liquids according to thecontents of the valuable materials, that is to say to recover two ormore separate liquids after contact with the battery components.

According to the invention in one aspect, there is provided a method oftreating a secondary battery comprising at least one componentcontaining alkali metal, comprising the step of introducing a gascontaining at least one of water vapor and alcohol vapor into a closedchamber containing at least this component, thereby to form alkali metalhydroxide or alkoxide. The chamber or the gas introduced may containsubstantially no oxygen gas, but atmospheric air may be used as acarrier gas for the water vapor.

The water content in the introduced gas is preferably in the range 0.5to 3 g per litre of gas. The gas temperature is preferably in the range100 to 150° C. The alcohol content is preferably in the range 0.5 to 5 gper litre of gas.

When processing a large amount of battery components, an abruptevolution of hydrogen may occur if water is added to alkali metalscontained in battery. A hydrogen explosion can take place if thehydrogen concentration is higher than 4% in air. However, the waterdecomposition method hardly controls the rate of hydrogen evolution,because water has an extremely high reactivity to alkali metals. On theother hand, addition of water vapor to battery components can solve thisproblem. Water vapor content in a gas is easily controlled, so that theevolution rate of hydrogen can be suppressed under the limit which makeshydrogen explosive.

At the initial stage of the processing of alkali metals included inbatteries, the water vapor content of the gas may be lower. The alkalimetal is gradually decomposed into hydrogen and alkali hydroxide. As thedecomposition rate decreases, the water vapor content is made higher tocontinue the decomposition reaction. After most of the active materialsis decomposed, then liquid water may be added to complete thedecomposition processing.

Instead of water vapor, alcohol vapor such as methanol, ethanol,propanol, butanol and the like is the alternative which can be used inprocessing alkali metals included in batteries at the initial stage. Thealcohol reacts with alkali metals yielding hydrogen and alkali metalalkoxides. As solubilities of the alkoxides in alcohols are low, theycover the surface of the active materials as the processing advances.Accordingly, water vapor or mixture of water vapor and alcohol vapor maybe supplied instead of the alcohol vapor. Water in the gas can decomposethe alkoxide into alkali hydroxides and alcohols, which are very solubleinto water. After most of the active materials is decomposed, liquidwater may be added to complete the decomposition processing.

For safety reasons, it is preferred to control the hydrogenconcentration. Preferably, the method includes controlling the hydrogengas concentration in the chamber to below 4% by volume. The hydrogenconcentration may be controlled by adjusting at least one of the rate ofintroduction of water or alcohol vapor into the chamber, the temperaturein the chamber and the temperature of the introduced gas. Suitably, atleast one of the water concentration in the gas and the temperature ofthe gas is increased during the treatment of the battery.

The method may include the step of contacting components of the batterywith an aprotic solvent to remove electrolyte therefrom, beforecontacting the component containing alkali metal with the introducedgas.

The invention in its method aspect can also provide a method of treatinga secondary battery comprising at least one component containing alkalimetal, to extract alkali metal therefrom, comprising the steps ofexposing the component containing alkali metal to a gas containing atleast one of water vapor and alcohol vapor so as to form alkali metalhydroxide or alkoxide, and separating the alkali metal hydroxide oralkoxide from other constituents of the battery.

The step of separating the alkali metal hydroxide may comprise addingwater to form a solution thereof and separating the solution fromremaining solid constituents.

Yet further, the invention provides a method of converting an alkalimetal in a secondary battery into alkali metal hydroxide or alkoxide bycontacting the alkali metal with water, wherein the improvementcomprises contacting the alkali metal with a gas containing at least oneof water vapor and alcohol vapor, and controlling the hydrogenconcentration by control of the supply rate of water vapor.

The invention also provides a method of converting alkali metal presentin a secondary battery to alkali metal hydroxide, comprising exposingthe alkali metal to a gas containing at least one of water vapor andalcohol vapor in a closed chamber and extracting hydrogen gas evolved insaid chamber by reaction of the vapor with the alkali metal, so as tomaintain a concentration of hydrogen gas in said chamber below apredetermined safe concentration thereof.

Apparatus according to the invention for treatment of a batterycomprising a component containing an alkali metal, comprises means foropening an outer casing of the battery, a closable chamber to receivethe battery, and means for introducing to said chamber a gas containingat least one of water vapor and alcohol vapor. Preferably there aremeans for separating alkali metal hydroxide formed by reaction with saidalkali metal from solid components of the battery.

This apparatus may have a hydrogen concentration sensor for sensinghydrogen concentration in the chamber and means for adjusting the rateof introduction of the water vapor or alcohol vapor in dependence on thesensed hydrogen concentration. Further, it may have a temperature sensorfor sensing temperature in the chamber and means for adjusting the rateof introduction of the water vapor or alcohol vapor in dependence on thesensed temperature.

In another aspect, the invention provides apparatus for treatment of abattery comprising a component containing an alkali metal, comprisingmeans for opening an outer casing of the battery, a closable chamber toreceive the battery, means for introducing to the chamber a gascontaining at least one of water vapor and alcohol vapor, a sensor formonitoring the reaction with alkali metal in said chamber and means forcontrolling the introduction of said gas in dependence on an output ofsaid sensor. The sensor is preferably selected from (a) a pressuresensor for sensing pressure in the chamber, (b) a temperature sensor forsensing temperature in the chamber and (c) a hydrogen concentrationsensor for sensing hydrogen concentration in the chamber.

In yet another aspect, the invention provides apparatus for treatment ofa battery comprising a component containing an alkali metal, saidapparatus comprising a closable chamber having a plurality ofintercommunicating compartments comprising at least (a) a firstcompartment provided with means for opening an outer casing of saidbattery, and (b) a second compartment having means for introducingthereto a gas containing water vapor for reaction with said alkalimetal.

The apparatus may include means for agitating, e.g. vibrating, thebattery components during the treatment or means for stirring thebattery components.

Further preferred and optional features of the invention and methods andapparatus of carrying it out will now be described generally.

To efficiently and safely decompose and recover active materials such asa battery active material and electrolytic solution contained in a highenergy density battery, the battery is processed while controlling thedecomposition rate of the target materials. The method of processing abattery according to the present invention has an advantage in that thedecomposition rate of an active material of the negative electrode canbe controlled by use of a processing gas containing the vapor of amaterial reactive with the active material, and further by adjusting atleast one of the supply rate, concentration and temperature of theprocessing gas. As for the electrolytic solution, it may be separatelyrecovered using a suitable cleaning liquid.

The battery processing apparatus of the present invention typicallyincludes a processing chamber for processing an active material of abattery in a controlled atmosphere, which may be based on a dry inertgas, nitrogen gas or air. It is desirable to prevent the entrapment ofan external water content in the processing chamber when a battery ismoved between the processing chamber and the outside of the apparatus.For this purpose, there is proposed a method of using an inlet chamber(lock chamber) capable of replacing the gas atmosphere from theatmospheric air with the dry gas by means of a vacuum pump. In thismethod, a port of the preparing chamber is first opened to move thebattery into the inlet chamber; the port is closed to allow evacuationof the atmospheric air in the preparing chamber; dry atmospheric gas isintroduced into the inlet chamber; and a port separating the inletchamber from the processing chamber is opened to allow the battery tomove into the processing chamber. In this method, since the processingchamber is not opened to the atmospheric air, the dry state in theprocessing chamber is maintained. Moreover, to improve the operabilityof the battery processing apparatus, to reduce the operational cost, andto shorten the battery processing time, there may be provided an inletchamber having an air curtain mechanism of a dry gas at the entry portof the processing chamber, thereby maintaining the dry state of theinterior of the processing chamber in a more simple manner as comparedwith the above-described gas replacement system.

Next, there will be described one preferred process of inactivating ahigh energy density battery containing an alkali metal. First, a batteryis completely discharged outside the apparatus of the present invention.A suitable method of discharging the battery is by short-circuiting theterminals of the battery by way of a resistor or by dipping the batteryin a solution containing sodium chloride or a dilute acid. In the lattermethod, the battery discharge is accompanied by corrosion of the batterycasing so that a large number of small size batteries, of the AA sizefor example, may be treated together at one time. After being dischargedin this way, the battery is carried into the processing chamber by wayof the inlet chamber. A drive type transporting device such as a beltconveyor may be provided between the inlet chamber and the processingchamber for easy movement of the battery therebetween. The inlet chamberhas a gas supply system and a gas exhaust system for communicating thedry atmospheric gas to the inlet chamber even when it uses either an aircurtain system or gas replacement system. Moreover, to exhaust acombustible gas such as hydrogen gas generated in the inactivation ofthe battery or a harmful gas such as PF₅ from the processing chamber,the processing chamber has a gas supply system and gas exhaust system.While the humidity in the processing chamber is controlled, the batterycomponents are exposed using a battery crusher, such as a hammercrusher, having a function of crushing the battery together with thecasing, or a battery disjointing device, such as a grinder or a diamondcutter, having a function of cutting the casing of the battery andtaking out the battery components. The processing chamber is connectedto a supply system and exhaust system of a processing gas and liquid.

After the battery components are exposed inside or outside the batterycasing, the electrolytic solution contained in the battery vessel,electrodes, separator and the like is removed using a cleaning liquid.As the cleaning liquid, there may be used an aprotic organic solventsuch as propylene carbonate, 1,2-dimethoxyethane, diethoxyethane or thelike. By distilling the waste cleaning liquid, the electrolyte can berecovered. Next, nitrogen gas, other inert gas (e.g. Ar or He) or aircontaining water or alcohol vapor in dilute form is introduced into theprocessing chamber, to gradually decompose the active material of thenegative electrode.

The water content in the introduced gas is preferably in the range 0.5-2g per litre, and the preferred temperature of the gas is in the range100-150° C. Relative humidity of the gas may be 80-100%. Alternatively,vapor of an alcohol such as methanol, ethanol, propanol and butanol ispresent in the gas. Preferable alcohol content in the processing gas is0.5-5 g per litre. A mixture of water vapor and alcohol vapor (e.g. inthe amounts given above), which is more reactive to alkali metal thanthe respective alcohol, is also useful in decomposition to alkalimetals. The processing is performed by injecting the processing gas tothe component. The processing gas may be introduced from the liquidsupply system connected to the processing chamber. At the initial stage,the processing gas decomposes the negative electrode, and it may becomeless reactive to the electrode in the progress of the processing. Inthis case, liquid water or a liquid mixture of water and alcohol issprayed or dropped onto the negative electrode. These liquids areintroduced from the supply system of the processing gas, if the vaporgenerator is switched off. The spent processing gas is exhausted fromthe processing chamber by way of the liquid exhaust system.

The concentration of hydrogen gas generated during the processing of thenegative electrode desirably should for safety reasons be less than theexplosion limit, preferably 4% or less. The hydrogen gas accumulating inthe processing chamber is readily exhausted from the processing chambertogether with the inert gas, nitrogen gas or air introduced into theprocessing chamber. A gas separator is mounted in the gas exhaust systemfor recovering hydrogen gas.

For execution of the above described process, there may be usedapparatus having a processing chamber and including: a processing gassupply system having storage vessels storing a plurality of processingmaterials, supply ports for processing gas, and a waste liquid exhaustsystem having exhaust ports for the spent processing liquids and wasteliquid storage vessels. For processing the negative electrode usingwater vapor, a humidifying device having a function for controlling thewater vapor concentration is mounted in the processing gas supplysystem. Gas flow rate control means are provided. A plurality of gassupply ports may be provided in the processing chamber; or supply portsfor introducing different processing gases to a plurality of processingchambers may be provided in a plurality of the processing chambers, toprocess the batteries using processing gases which are different inreactivity in a stepwise manner from each other. The gas supply meansmay apply liquids, when the gas supply is stopped.

The automation of the operation of the above-described batteryprocessing apparatus is desirable to improve the efficiency and safetyof the processing of the battery. To automate the apparatus, there areprovided for example a flow rate controller for controlling the supplyamount and exhaust amount of processing gas; a sensor for measuring thepressure, temperature and hydrogen concentration in the processingchamber; and an arithmetic and control unit for controlling the flowrate controller of the processing gas according to the state of theprocessing chamber monitored by the sensor. The flow rate controllersmay be provided in the supply pipe and exhaust pipe connected to theinlet chamber and the processing chamber. The sensor is provided in theprocessing chamber, and may include a temperature sensor, infrared raysensor or hydrogen sensor. The measured data such as the temperature andthe hydrogen concentration in the processing chamber are transmittedfrom the sensor to the arithmetic control unit. The arithmetic andcontrol unit operates the flow rate controllers and vapor generatorsaccording to the analyzed result of the measured data for adjusting thesupply amount and exhaust amount of the processing gas or liquid, andthe temperature of the gas and the vapor content, as desired. When anabnormal decomposition rate occurs midway in the processing of thebattery, the introduction of the processing gas may instantly be stoppedor a large amount of an inactive liquid may be added to the activematerial being decomposed, to suppress the decomposition. Moreover, itis possible to easily exhaust the combustible gas such as hydrogen whichmay be excessively generated, through the exhaust system. Byincorporating such a controlling system in the apparatus, the operationof the battery processing apparatus can be automated, thus improving theefficiency and safety of the decomposition process of the battery.

Various materials can be recovered from the solutions produced by themethods of the invention. Alkali metal can be extracted from thehydroxide by distilling to obtain oxide, followed by electrolysis.Electrolyte may be recovered by vacuum distillation. Other metals suchas Co, Ni, Fe and Al can be recovered from the battery components also,by processes such as incineration, reduction and electrolysis.

The cost required to recover valuable materials from the waste liquid inprocessing of the battery is dependent on the concentration of thetarget material contained in the waste processing liquid exhausted fromthe battery processing apparatus. For recovering the target materialfrom the waste liquid having a low concentration, a process of enrichingthe waste liquid by extraction or distillation is required, whichincreases the recovery cost. In the present invention, it becomespossible to fractional-recover the waste processing liquid exhaustedfrom the battery processing chamber, to enrich only the processingliquid low in the concentration of the valuable material, and to recoverthe valuable material from all the waste processing liquid. Materialswhich may be recovered are alkali metals and transition metals such asFe, Ni, Mn, Co. Alkali metal may be obtained by extraction andelectrolysis, while transition metals may be obtained by variousmetallurgical processes such as incineration, reduction andelectrolysis. The battery processing apparatus of the present inventionmakes it possible to fractional-recover the waste processing liquids ofvaluable materials having different concentrations, and to reduce thecost in regenerating the valuable materials.

In the case of using water vapor as a reactive material for decomposingthe negative electrode, a carrier gas such as an inert gas, nitrogen orair mixed with water vapor is contacted with the negative electrode, todecompose the active material of the negative electrode. When usingwater and alcohol vapors, the contents in the carrier gas may becontrolled by varying the mixing ratio of alcohol and water. At theinitial stage of decomposition, the concentration of water and/oralcohol vapor is kept low to reduce the reactivity of the processing,thus suppressing the abrupt decomposition of the active material of thenegative electrode. As the decomposition proceeds, decompositionproducts such as alkoxides become deposited on the surface of thecomponent. By increasing the water and/or alcohol vapor concentration asthe decomposition rate of the negative electrode is lowered, thereactivity of the gas is increased and decomposition of the negativeelectrode is continued. Finally, liquid water may be directly contactedwith the negative electrode, thus completing the decomposition andsolution of the alkali metal as hydroxide. This method is effective toreduce the cost of the processing liquid and to reduce the environmentload due to the waste processing liquid.

The processing gas may initially contain an alcohol, or the alcohol maybe included after an initial period when water vapor only is present inthe processing gas. The water vapor reacts to generate alkali metalhydroxide. If a solution is produced in the chamber, it may be removedas it is, or water may be added, when the reactivity of the batteryresidue is much reduced, to form a solution to be withdrawn.

INTRODUCTION OF THE DRAWINGS

Embodiments of the invention will now be described by way ofnon-limitative example, with reference to the accompanying drawings, inwhich:

FIG. 1 is a diagrammatic view of a lithium battery processing apparatusincluding ports with a sliding type door according to one embodiment ofthe present invention.

FIG. 2 is a diagrammatic view of a lithium battery processing apparatusin which the processing chamber is partitioned by a partitioning plateaccording to another embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the several drawings, the same reference numerals identify the sameor corresponding elements.

FIG. 1 shows a battery processing apparatus of the present invention,which includes a processing chamber 1 and inlet and outlet chambers 2aand 2b respectively connected to opposite sides of the processingchamber 1. The processing chamber 1 and each of the chambers 2a and 2bhave outer sizes of 1 m×1 m×2.5 m and 0.5 m×0.5 m×1 m, respectively.Ports 3a and 3b, each having an opening/closing plate, are respectivelymounted at the outer side of the chambers 2a and 2b for maintaining theair-tightness of the chambers 2a and 2b. Ports 4a and 4b, each having anopening/closing plate, are provided between the chambers 2a and 2b andthe processing chamber 1. A belt conveyor indicated at 5 is providedwithin this apparatus for transporting a battery, battery components andthe like. Three sets of gas supply systems including a gas supply device6 for drying and supplying an atmospheric gas, gas supply pipes 7a, 7band 7c, and valves 8a, 8b and 8c are connected to the processing chamber1 and the inlet and outlet chambers 2a and 2b. In this embodiment, asthe atmospheric gas, nitrogen gas is used.

To recover the hydrogen gas generated in the processing chamber 1 duringthe processing of a battery, the gas in the processing chamber 1 istransported to a gas separator 9 by way of a gas exhaust pipe 10 havinga valve 8d. The hydrogen is separated from the gas at the gas separator9, and is recovered in a gas storage vessel 14 connected to atransporting pipe 13 having a valve 8f. To store hydrogen gas, ahydrogen storage alloy such as LaNi₅ is present in the gas storagevessel 14. The nitrogen gas remaining in the gas separator 9 istransported to the gas supply device 6 by way of a transporting pipe 11having a gas transporting pump 12 and a valve 8e. Upon decomposition ofa negative electrode, nitrogen is circulated by opening the valves 8b,8d and 8e and continuously driving the pump 12.

The apparatus has means 21b for supplying humidified air via a flow ratecontrol valve 22b, an optional liquid pump 23b through a pipe 25b andvia a heater 29 to an injector 24b in the processing chamber. The watervapor content of the air can be adjusted. This arrangement is alsocapable of supplying liquid water. Alternatively, separate means forsupplying humidified gas and liquid water respectively may be provided.

EXAMPLE 1

In this example, five 3 Wh lithium secondary batteries are processed,each of which includes a positive electrode made of LiCoO₂, a negativeelectrode made of a lithium-lead alloy, and an electrolyte made of anorganic electrolytic solution containing LiPF₆. The battery has acylindrical shape having a diameter of 18 mm .o slashed. and a length of65 mm. First, outside the battery processing apparatus shown in FIG. 1,each battery was short-circuited by way of a resistor of 10Ω to beperfectly discharged. The port 3a was opened, and each battery 15 wasplaced on the belt conveyor 5 in the inlet chamber 2a, after which theport 3a was closed. The valve 8a was then closed and a valve 17a mountedin a gas exhaust pipe 16a was opened.

After that, an exhaust pump 18a was operated, to evacuate air present inthe inlet chamber 2a. After the inlet chamber 2a was evacuated, thevalve 17a was closed and the pump 18a was stopped. Next, dry nitrogengas was supplied to the inlet chamber 2a by way of the gas supply pipe7a. The port 4a was then opened, and the batteries 15 were moved to theprocessing chamber 1, after which the port 4a was closed.

The casing of the batteries was crushed in the processing chamber 1 bymeans of a battery crusher 19 including a hammer crusher and a cuttermixer. The crushed pieces were stored in a polypropylene vessel 20having its bottom surface provided with a polypropylene fibre meshmaterial as a filter. The time required for crushing was 20 min.

In this example, 1,2-dimethoxyethane is used for cleaning theelectrolytic solution adhering to the battery crushed pieces. A liquidstorage vessel 21a, in which 1,2-dimethoxyethane is stored, is connectedto the processing chamber 1 by means of a pipe 25a including a valve22a, a liquid transporting pump 23a and a sprayer 24a.1,2-dimethoxyethane in an amount of 1 litre was sprayed onto the batterycrushed pieces stored in the vessel 20 at a rate of 100 ml/min, to cleanthe electrolytic solution from the battery pieces. The bottom surface ofthe processing chamber 1 was formed in a conical shape at two portionsfor collecting the cleaning liquid supplied from the sprayer 24a. Thecollected cleaning liquid was stored in a waste liquid storage vessel28a by way of a processing liquid exhaust pipe 27a having a valve 26a.

Next, the belt conveyor 5 was driven, and the vessel 20 was carried to aportion under the injector 24b.

A telescopic joint capable of adjusting height was mounted on the liquidsupply pipe 25b and the injector 24b was attached at the leading endthereof. The injector 24b was moved to be close to the vessel 20containing the crushed battery pieces, and it injected air at 100° C.containing water vapor with a humidity of 90% to the crushed pieces at arate of 1000 ml/min. Water bubbles were gradually generated from thecrushed pieces, to thus decompose the active material of the negativeelectrode.

After an elapse of 25 min, the heater 29 heated the humidified air to150° C. The humidified air was then further injected onto the crushedpieces for 30 min at the same rate. Next, the supply of the humidifiedair from means 21b was stopped, and only water was supplied from themeans 21b, so that water was added to the battery crushed pieces by thepump 23b at a rate of 100 ml/min. The waste water was stored in thewaste liquid storage vessel 28b by way of the pipe 27b. After an elapseof about 15 min, the desired decomposition of the crushed pieces wascompletely finished, and the battery crushed pieces were then taken fromthe preparing chamber 2b as described below.

The hydrogen gas generated during treatment of the batteries wasexhausted to the gas separator 9 by way of the gas exhaust pipe 10together with air. The hydrogen gas recovered by the gas separator 9 wasstored in the storage vessel 14 including LaNi₅ alloy by way of the pipe13 having the valve 8f which was opened, and was stored in the storagevessel 14 including LaNi₅ alloy. The gas remaining in the gas separator9 was returned to the gas supply device 6 by way of the pipe 11.

To remove the residue of the batteries, the atmospheric air in thechamber 2b was exhausted by a gas exhaust system including a valve 17b,a pump 18b and a gas exhaust pipe 16b. The valve 17b was then closed,after which the valve 8c was opened and dry nitrogen was introduced intothe outlet chamber 2b by way of the gas supply pipe 7c. After thechamber 2b was filled with dry nitrogen, the plate of the port 4b wasopened, and the vessel 20 was moved into the outlet chamber 2b. Theplate of the port 4b was closed and the plate of the port 3b was thenopened, and thus the vessel 20 containing the crushed pieces was takenfrom the chamber 2b.

The waste water stored in the waste liquid storage vessel 28b wasdistilled and the lithium metal was recovered by electrolytic refining.Lithium was recovered from the crushed residue by extraction andelectrolysis. The recovered ratio of lithium was 95% based on the totalamount of lithium contained in five cylindrical lithium secondarybatteries.

From the 1,2-dimethoxyethane solution of LiPF₆ stored in the wasteliquid storage vessel 28a, LiPF₆ was recovered by vacuum distillation.

EXAMPLE 2

50 cylindrical lithium secondary batteries each having the samespecification as those processed in the Example 1, were previouslydischarged in a salt water containing sodium chloride or the like andprocessed in the battery processing apparatus shown in FIG. 1. First,each lithium battery was dipped for two days in a salt water containingsodium chloride in an amount of 50 g per 2 l of water. By this, part ofthe battery vessel was corroded. Each battery was carried into theprocessing chamber 1 by the same procedure as in Example 1, and wascrushed using the battery crusher 19 having the hammer crusher and thecutter mixer. The crushed pieces were then stored in the polypropylenevessel 20 having the bottom surface provided with the mesh. The timerequired for crushing the batteries was 20-23 min. The batteries in thenumber being 10 times that of the batteries in the Example 1 werecrushed for about the same time. As in this embodiment, by corroding thevessel of the batteries in a solution containing a salt such as sodiumchloride or potassium chloride or a diluted hydrochloric acid, the timerequired for crushing of batteries could be shortened even when thenumber of the batteries was increased. 1,2-dimethoxyethane stored in theliquid storage vessel 21a was added to the battery crushed pieces for 20min at a rate of 100 ml/min, to clean the electrolytic solution stuck onthe crushed pieces. The waste cleaning liquid was stored in the wasteliquid storage vessel 28a. Subsequently, water stored in the liquidstorage vessel 21b was heated at the heater 29 to produce an air-watervapor mixture gas containing 0.5 g water per 1 l at 100° C. The gas wasinjected onto the crushed pieces of the batteries at a rate of 1 l/minfor 40 min. During decomposition of lithium-lead alloy particules in thecrushed materials, the hydrogen concentration in the processing chamberwas kept below 0.5% or less. No evolution of hydrogen from the crushedpieces was observed after supplying the gas for an elapse of 60 min.Finally 1 l of liquid was added to the crushed pieces to terminatedecomposition of the lithium alloy. In this example, the total timerequired for processing fifty 3 Wh lithium secondary batteries 15 wasabout 1.8-2.0 hr. The volume of aqueous liquid containing lithium ionsrecovered in the waste liquid storage vessel 28b was 0.8-0.9 l. Byelectrolytic refining, 20% of lithium metal contained in the originallithium batteries was recovered. From the residue obtained from thevessel 20, lithium cobalt, iron, and aluminium was re-generated byincineration and reduction or electrolysis. Nearly 85% of the totalamount of lithium metal in the lithium batteries was recovered. Theregenerated amounts of cobalt, iron and aluminium were 75˜80% of theamounts initially contained in the batteries. From the1,2-dimethoxyethane solution of LiPF₆ remaining in the waste liquidstorage vessel 28a, 93% of LiPF₆ was recovered by vacuum distillation.

EXAMPLE 3

Using five pieces of the lithium batteries having the same specificationas those in the Example 1, an experiment was made to shorten the timerequired for processing the batteries. 1,2-dimethoxyethane was used as acleaning liquid for recovering an electrolytic solution of thebatteries. Each battery was crushed using the battery crusher 19 havingthe hammer crusher and the cutter mixer in the same procedure as in theExample 1. The crushed pieces were stored in the polypropylene vessel 20with a polypropylene filter. 1,2-dimethoxyethane in an amount of 1 l wasadded to the crushed battery components at a rate 100 ml/min from thesprayer 24a. The waste cleaning liquid was stored in the waste liquidstorage vessel 28a. The vessel 20 containing the battery crushed pieceswas placed directly under the injector 24b. First, in such a state thatthe heater 29 was operated, gas at 150° C. was injected onto the batterycrushed pieces at a rate of 1 l/min from the injector 24b using nitrogengas carrier. Water content was 1 g per litre. The time required forsupplying the processing gas was 30-35 min. The hydrogen concentrationin the processing chamber 1 during the processing of the negativeelectrode was 1% or less, and accordingly the negative electrode couldbe safely decomposed without the fear of explosion of hydrogen. Water inliquid form was added to complete the decomposition. The waste liquidstored in the waste liquid storage vessel 28a was distilled in vacuum,and thereby 95% of the total LiPF₆ contained in the batteries wasrecovered. The waste liquid stored in the waste liquid storage vessel28b was subjected to electrolytic refining, to recover 25% of the totallithium metal contained in the batteries. From the residue obtained fromthe vessel 20, lithium, cobalt, iron, and aluminium was regenerated byincineration and reduction or electrolysis. Nearly 83% of the totalamount of lithium metal in the lithium batteries was recovered. Theregenerated amounts of cobalt, iron and aluminium were 75˜80% of theamounts initially contained in the batteries.

EXAMPLE 4

The battery processing time may be shortened by agitating crushedbattery components during supply of the gas. Five pieces of the lithiumsecondary batteries having the same specification as those in Example 1were processed. Each lithium battery was discharged through a resistorof 10 Ω and was crushed using the battery crusher 19 having the hammercrusher and the cutter mixer in the processing chamber 1. The crushedpieces were put in the polypropylene (PP) vessel 20 with the PP filter.They were cleaned with 1,2-dimethoxyethane supplied from the liquidstorage vessel 21a. The processing gas contains water vapor at 0.5 g/lat 100° C. It was supplied from the nozzle 24b to the crushed pieces ofbatteries in the PP vessel 20. The flow rate of processing gas was 1l/min. Next, a rotary mixer was inserted in the vessel 20 containing thebattery crushed pieces, and the pieces were agitated. After thegeneration of hydrogen was no longer observed from the crushed pieces,the liquid product was discharged from the vessel 20 to the waste liquidstorage vessel 28b by way of the liquid exhaust pipe 27b. Finally, 1 lof water at 25° C. was added to the crushed pieces from the nozzle 24b,after the steam generator 29 was switched off. The decomposition time bythe gas was 18-20 min, and the total battery processing time was 1.3-1.4hr. The battery processing time was shortened compared with Example 1 bythe agitation of the crushed component. The waste liquid stored in thewaste storage vessel 28a was distilled in vacuum, so that 95% of thetotal LiPF₆ contained in the batteries was recovered. The wasteprocessing liquid stored in the waste liquid storage vessel 28b and theresidue of the crushed battery pieces was subjected to electrolyticrefining, to recover 80% of the total lithium metal contained in thebatteries.

In FIG. 1 a hydrogen sensor 30 having a function of detecting thehydrogen concentration in the processing chamber 1 is provided in theprocessing chamber 1. The hydrogen sensor 30 was connected to anarithmetic and control unit 32 though a signal input cable 31. Thearithmetic and control unit 32 is connected to the flow rate adjuster22b and the liquid supply pump 23b by means of signal input cables 33aand 33b, respectively. The hydrogen sensor 30 measures the hydrogenconcentration in the processing chamber 1, and transmits an electricsignal proportional to the measured value to the arithmetic and controlunit 32. The arithmetic and control unit 32 calculates the electricsignal supplied from the hydrogen sensor 30, and transmits the electricsignal corresponding to the processing result to the flow rate adjuster22b or the liquid supply pump 23b for controlling their operation. Inthis embodiment, the allowable value of hydrogen concentration and thetotal supply amount of the processing gas are previously stored in amemory unit of the arithmetic and control unit 32, and the calculatingcondition of the arithmetic and control unit 32 may for example be inaccordance with the following items (1) to (5) singly or in combination.

(1) When the hydrogen concentration in the processing chamber 1 issmaller than the allowable value, the arithmetic and control unit 32controls the flow rate adjuster 22b for increasing the supply rate ofthe processing gas. In this embodiment, the permitted hydrogenconcentration in dry gas is within the range from 0 to 4%.

(2) When the average hydrogen concentration in the processing chamber 1is less than 0.01% for a selected period, e.g. in the range 1 to 5minutes, the supply of processing gas or liquid is stopped.

(3) When an electric signal transmitted from the hydrogen sensor 30 tothe arithmetic and control unit 32 is abruptly increased to more than ahydrogen concentration allowable value, the flow rate adjuster 22b andpump 23b are closed by way of the signal input cables 33a and 33b, tostop the processing supply. The hydrogen concentration allowable valuein this case may be set at 10%.

(4) The arithmetic and control unit 32 accumulates the supply amount ofthe water and the accumulated value is stored in the memory unit of thearithmetic and control unit 32.

(5) When the accumulated value in (4) reaches the upper limit of thetotal supply amount of the processing water stored in the memory unit ofthe arithmetic and control unit 32, the flow rate adjuster 22b and pump23b are closed.

EXAMPLE 5

The apparatus shown in FIG. 1 was operated under the control conditionsdescribed above. Five lithium batteries 15 of the same specification asthose in Example 1 were crushed in the battery crusher 19 and theelectrolyte was cleaned off as in Example 1. Then the active materialsof the negative electrodes were decomposed with the water vaporcontaining gas. The gas contained water of 0.5 g/l at 100° C., and thecarrier gas was nitrogen. It was supplied from the nozzle 24b to thecrushed pieces of the batteries. The processing time was 25 min. Afterthis treatment, water (1 l) was added to the pieces from nozzle 24b. Thewater amount supplied from the liquid storage vessel 21b was 41. Thetotal time required for putting the batteries in the processingapparatus and taking the battery crushed pieces from the processingapparatus was 1.4-1.5 hr. The waste cleaning liquid stored in the wasteliquid storage vessel 28a was distilled in vacuum, so that 95% of thetotal LiPF₆ of the batteries was recovered. The water processing liquidstored in the waste liquid storage vessel 28b was subjected toelectrolytic refining, and 23% of the total lithium metal of thebatteries could be recovered. Metallurgical methods such as extractionand reduction recovered 60% lithium from the crushed pieces. In thisembodiment, as compared with Example 1, it becomes possible to shortenthe battery processing time, and to automate the battery processingallowing unmanned operation.

In a variation of the embodiment of FIG. 1, to shorten the batteryprocessing time, the preparing chambers 2a and 2b each have an aircurtain mechanism. The ports 3a, 3b, 4a and 4b include sliding typeopening/closing plates. In this apparatus, the gas storage vessel 6 wasreplaced by a supply device 6 for usually supplying dry air to theprocessing chamber 1 and the preparing chambers 2a and 2b. Moreover, thegas exhaust pumps 18a and 18b were not required. When the port 3a wasopened, dry air was supplied from the dry air supply device 6 to thepreparing chamber 2a. The dry air was discharged to the exterior of theapparatus through the gas exhaust pipe 16a by opening of the valve 17a.With this air curtain mechanism, humidified air outside the apparatuswas not permitted to enter the processing chamber 1. Even when theprocessed battery components were taken from the preparing chamber 2b,dry air was supplied from the dry air supply device 6 to the preparingchamber 2b, and was communicated to the gas exhaust pipe 16b by openingof the valve 17b.

EXAMPLE 6

Five lithium batteries of the same specification as in Example 1 wereprocessed in the modified apparatus just described, by the procedure ofExample 3. The time required for the processing of the negativeelectrode by gas containing water vapor was 25-30 min as in Example 3,and the time required for crushing of the batteries was the same as inthe Example 3. The hydrogen concentration in the processing chamber 1during reaction between ethanol and the battery crushed pieces wasmaintained at 1% or less. In this embodiment, the gas replacement in theinlet and outlet chambers 2a and 2b was eliminated, thus shortening thetotal processing time to be 1 hr.

FIG. 2 is a battery processing apparatus in which two sets of processingfluid supply systems and liquid exhaust systems are independentlyprovided. A partitioning plate 34 is provided in the upper portion ofthe processing chamber 1 to provide two working areas and sprayers 24aand 24b are provided in the upper portion of the processing chamber 1.Diethoxyethane for cleaning electrolytic solution is stored in a liquidstorage vessel 21a, and is introduced from the sprayer 24a to the firstcompartment of the processing chamber 1 by way of a liquid transportingpipe 25a having a valve 22a and a pump 23a. Ethanol and water are storedin vessels 21b and 21c and are supplied with a carrier gas (dry air) fordecomposing a negative electrode from the injector 24b to the secondcompartment of the processing chamber 1 by way of pipe system 25b havingvalves 22b and 22c and pump 23b and 23c. The supply means 21b can alsosupply water vapor only in air, if required. For example a mixture of50% ethanol and 50% water by weight is supplied. The liquid supply means21b and 21c have the capability of generating vapors of the liquids byheating.

To individually recover the cleaning liquids or processing liquids usedin the partitioned areas, two portions of the bottom surface of theprocessing chamber 1 were formed in a conical shape, and two wasteliquid exhaust pipes 27a and 27b are connected to the two portions. Asanother method of recovering waste liquids, a partitioning plate isarranged on the bottom surface of the processing chamber 1 under thebelt conveyor 5, so that the waste liquids can be fractional-recoveredwithout any mixing of the waste liquids. Valves 26a and 26b control thewaste liquid exhaust pipes 27a and 27b, respectively. Dry air to besupplied to the processing chamber 1 and the inlet/outlet chambers 2aand 2c was introduced to the apparatus from a gas supply device 6 havinga function of drying air. The dry air was continuously supplied from thegas supply device 6 to the chambers 2a and 2b of the battery processingapparatus by way of a pipe 7a, and was exhausted from a gas exhaust pipe16a by opening of the valve 17a.

EXAMPLE 7

The lithium battery used in this example is a square lithium secondarybattery including a positive electrode made of LiCoO₂, a negativeelectrode made of carbon electrochemically absorbing and releasinglithium ions, and an electrolyte made of organic electrolytic solutionin which LiPF₆ is dissolved in a mixture of 50 vol % of ethylenecarbonate and 50% vol of 1,2-dimethoxyethane. The battery has a size of50 mm×80 mm×40 mm, and a rating capacity of 30 Wh. In this embodiment,five of these batteries were processed. First, each battery 15 wasdischarged using a resistor of 10 Ω outside the battery processingapparatus shown in FIG. 2. The sliding plate 3a of the inlet chamber 2awas opened, and each battery 15 was placed in the chamber 2a. The plate3a was closed and the plate 4a was opened, and the batteries 15 wascarried into the processing chamber 1. A battery disjointing machine 19having a diamond cutter and a cutter mixer was provided in theprocessing chamber 1. The upper portion of each battery vessel was cutusing the diamond cutter of the battery disjointing machine 19. Theupper portion of each battery 15 was removed, and battery componentswere taken out from the battery vessel.

The electrolytic solution on a separator, the battery vessel andelectrodes was cleaned by 1,2-dimethoxyethane supplied from the sprayer24a. The waste cleaning liquid was stored in a waste liquid storagevessel 28a by way of a liquid exhaust pipe 27a. The cleaned negativeelectrode was finely cut using the cutter mixer of the batterydisjointing machine 19, and was stored in the PP vessel 20 having thebottom surface provided with a PP filter. The other battery members wereplaced on a belt conveyor 5 as they were. The belt conveyor 5 wasdriven, and the vessel 20 was moved directly under the nozzle 24b. Thenozzle 24b provided the air containing ethanol and water vapor at 50/50%weight ratio (total 0.5-3.0 g/l) at 3 l/min to the negative electrode inthe vessel 20. The processing time was 50 min.

The hydrogen concentration in the processing chamber 1 was 3% or less.After an elapse of about 40 min from the start of the processing,hydrogen was difficult to be generated as lithium alcoholate (alkoxide)with white color was precipitated, and the hydrogen concentration in theprocessing chamber 1 was 0.1% or less. After the supply of theethanol+water vapor was stopped, the flow rate controller 22c wasstopped, and only the air containing water vapor at 0.5 g/l was added tothe negative electrodes from the nozzle 24b. The flow rate of air was 3l/min. This processing time was 30 min. Finally, the air flow wasswitched off, and water (5 l) was supplied to the crushed pieces of thebatteries.

The plate 4b was opened, and the vessel 20 and the electrode memberswere carried into the outlet chamber 2b. The plate 4b was closed and theplate 3b was opened, for removal of all of the processed batterycomponents. The total time required for processing of the five batterieswas 2.2-2.3 hr. The total volumes of the ethanol and water used in theprocessing of the negative electrodes were about 0.5 l and 6 l,respectively. In all of the processes of this embodiment, the hydrogenconcentration in the processing chamber 1 was suppressed to be 3% orless. The waste liquid in the waste liquid storage vessel 28a wasdistilled in vacuum, so that 95% of the total LiPF₆ contained in thefive batteries could be recovered. The waste liquid obtained in thewaste liquid storage vessels 28b was distilled, so that 30% of the totallithium contained in the batteries was recovered by electrolyticrefining. From the crushed pieces obtained after the deactivation ofnegative electrodes, lithium was reproduced by extraction and reduction.The lithium amount was 55% of the total amount of lithium included inthe batteries.

A battery having energy capacity being 10 times that of the lithiumsecondary battery processed in FIG. 1 can be continuously processedusing the battery processing apparatus shown in FIG. 2. The processingtime for each battery can be short, and the hydrogen generated uponprocessing was recovered in a produced gas storage vessel 14 containingLaNi₅ alloy, thereby ensuring the safety of the process. The wasteprocessing liquids from respective processing chambers can be stored inseparate tanks. This makes it possible to regenerate the electrolyte andlithium by fractional-recovering them, to simplify the distillation ofthe waste liquid stored in the waste liquid storage vessel 28bcontaining lithium ions of a high concentration, and to reduce the costrequired in the process of enriching the waste liquid by thefractional-recovery.

EXAMPLE 8

A cylindrical 3 Wh lithium secondary battery including a positiveelectrode made of V₆ O₁₃, a negative electrode made of Li metal, and asolid high molecular electrolyte made of a mixture of polyethylene oxideand LiCF₃ SO₃ was processed using the battery processing apparatus shownin FIG. 2. In the same procedure as in the Example 6, five of thelithium secondary batteries were carried into the processing chamber 1,and were crushed using the battery crusher 19 having the hammer crusherand cutter mixer. The crushed pieces were put in the PP vessel 20 havingthe bottom surface provided with the PP filter. 1,2-dimethoxyethanestored in the liquid storage vessel 21a was sprayed from the sprayer 24aonto the crushed pieces. The waste cleaning liquid was stored in thewaste liquid storage vessel 28a by way of the liquid exhaust pipe 27a.The vessel 20 was then moved directly under the nozzle 24b by the beltconveyor 5, and the nozzle 24b injected the ethanol and water vapor asused in Example 6 onto the crushed pieces in the vessel 20. Theprocessing time was 20 min. After 15 min the hydrogen generating ratewas decreased. Then air containing 0.5 g water in 1 l was supplied fromthe nozzle 24b. The unreacted alloy contained in the negative electrodewas started to be decomposed, and hydrogen was generated. The processingtime was 20 min. The waste liquid in the waste liquid storage vessel 28awas distilled in vacuum, so that 90% of the total LiPF₆ contained in thefive batteries was recovered. The waste liquid obtained in the wasteliquid storage vessel 28b was distilled, and 25% of the total lithiumcontained in the batteries was recovered by electrolytic refining. Therecovered lithium from the crushed battery pieces was 57-60% of thetotal amount.

While the invention has been illustrated by several embodiments, it isnot limited to them, and many variations, modifications and improvementsare possible, within the scope of the inventive concept.

What is claimed is:
 1. A method of treating a secondary batterycomprising at least one component containing alkali metal, comprisingthe step of introducing a gas containing at least one of water vapor andalcohol vapor into a closed chamber containing at least said component,thereby to form at least one of alkali metal hydroxide and alkoxide. 2.A method according to claim 1 wherein said chamber contains no oxygengas.
 3. A method according to claim 1 comprising opening a casing ofsaid battery in said chamber to expose said component containing alkalimetal, before introducing said gas containing water vapor.
 4. A methodaccording to claim 1 comprising controlling hydrogen gas concentrationin said chamber to below 4% by volume.
 5. A method according to claim 1comprising controlling the hydrogen concentration in said chamber byadjusting at least one of (a) the rate of introduction of said watervapor or alcohol vapor into said chamber and (b) the temperature of saidgas introduced into said chamber.
 6. A method according to claim 1wherein said gas comprises a carrier gas selected from air and an inertgas.
 7. A method according to claim 1 wherein said gas contains bothwater vapor and alcohol vapor.
 8. A method according to claim 1 whereinat least one of the water concentration in said gas and the temperatureof said gas is increased during the treatment of said battery.
 9. Amethod according to claim 1 comprising the step of contacting thecontents of said battery with an aprotic solvent to remove electrolytetherefrom, prior to contacting said component containing alkali metalwith said gas.
 10. A method according to claim 1 wherein said alkalimetal is lithium in the form of lithium metal, a lithium alloy or anintercalated lithium compound.
 11. A method of treating a secondarybattery comprising at least one component containing alkali metal, toextract alkali metal therefrom, comprising the steps of exposing saidcomponent containing alkali metal to a gas containing at least one ofwater vapor and alcohol vapor to form at least one of alkali metalhydroxide and alkoxide, and separating said alkali metal hydroxide oralkoxide from other constituents of the battery.
 12. A method accordingto claim 11 comprising placing said battery in a closed chamber andintroducing said gas into said chamber.
 13. A method according to claim11 said comprising adding water to form a solution of alkali metalhydroxide after contacting said component with said gas and separatingsaid solution from remaining solid constituents.
 14. A method ofconverting an alkali metal in a secondary battery into alkali metalhydroxide by contacting the alkali metal with water, wherein theimprovement comprises contacting said alkali metal with a gas containingat least one of water vapor and alcohol vapor, and controlling hydrogenconcentration by control of the supply rate of water vapor.
 15. A methodof converting alkali metal present in a secondary battery to alkalimetal hydroxide, comprising exposing said alkali metal to a gascontaining at least one of water vapor and alcohol vapor in a closedchamber and extracting hydrogen gas evolved in said chamber by reactionof the gas with the alkali metal, so as to maintain a concentration ofhydrogen gas in said chamber below a safe concentration thereof.